I usually get my PCBs made by OSH Park. They have pretty good pricing and pretty much the highest quality boards available. They are fast and easy to use. There are other good manufacturers, too, but so far OSH Park has more than met my needs. When I get into higher volume production (500+ boards), I'll probably check out other places.

Im new here too. I have been using AllPCB. So far I have had 3 batches (85 boards altogether). The quality is good enough for my purposes so far(i have been running meaurements against them). I would guess that all 3 batches are from seperate factories as the solder mask are slightly different shades. Price is good, and shipping times are amazing. Unless your boards are really demanding, they should be good enough.

Depends on size and purpose.I normally go to https://pcbshopper.com/ and take whatever looks best. If a small (less than 10cm*10cm) prototype I just go with the cheapest one which in the past been Elecrow.For a bit bigger board EasyEDA has been nice to me.

Ive tried a few but I really like elecrow for a few reasons.They are super helpful if they find anything wrong in the design, I get the feeling that they actually care.They dont put in any extra markings for manufacturing.Super fast with answering any stupid question from me